How do I Build an Earthen Roof?
An earthen roof is a covering made up of organic materials--soil, plants, grass and other types of vegetation. Earthen roofs provide many advantages, including longevity, effective insulation, cooling and protection, and improved aesthetics. The insulating and cooling properties of earthen roofs made them popular during the energy crisis resulting from the 1973 oil embargo. Today, energy efficiency is once again on homeowners' minds. But installing such a roof takes a great deal of time and effort to ensure it is done correctly. Does this Spark an idea?
Other People Are Reading
Things You'll Need
- Ladder
- Waterproof membrane
- Polyethylene
- 2-inch sheets of polystyrene insulation
- Duct tape
- Composite draining matting
- Tape measure
- 4-by-4 pressure-treated wooden timbers (amount will depend on size of roof)
- Drill (corded or cordless)
- 3-inch exterior grade wood screws with Phillips head
- 1/8-inch wood drill bit
- Phillips screwdriver bit for drill
- Circular saw
- Soil
- Plants
- Gardening tools
Instructions
-
-
1
Consult with a licensed building/construction engineer and have your building plans checked to ensure the roof structure will be capable of supporting the weight of the earthen roof.
-
2
Apply a waterproof membrane over the roof, making sure to cover all seams or openings where water could enter the building.
-
-
3
Place sheets of polystyrene insulation on top of the waterproof membrane. Duct-tape the sheets together at all seams.
-
4
Add a layer of polyethylene (at least 6-mil-thick) on top of the polystyrene. Tape the sheets together at all seams.
-
5
Install composite draining matting.
-
6
Build a frame around the perimeter of the roof to retain the earthen roof using 4-by-4 wooden timbers. Lay the timbers out first--do not fasten them together. After the entire frame is laid out, fasten the timbers together with the 3-inch screws. Making a starter hole with the drill bit will make it easier to drive in the screws.
-
7
Lay down a 4-inch layer of top soil and plant the vegetation.
-
1
Tips & Warnings
You can build an earthen roof on a pitched or slanted roof as long as you install a border secured to the roof. Just make sure the border is as high as the depth of the soil.
If you install a border, it is critical that you place the 4-by-4 timber frame on top of the composite draining mat. Do not cover the end or edge of the composite draining mat because you will prevent draining. Excess water could accumulate, causing a leak into the home or roof collapse due to weight.
